Write in the prepositions at, in, of where necessary. Complete the sentences about you

1. What is steel?

Steel is an alloy of iron and carbon.

2. What are the main properties of steel?

 Steel is strong and stiff.

3. What are the drawbacks of steel?

Steel corrodes easily through rusting.

4. What kinds of steel do you know?

We know stainless steel, low-carbon steels, medium-carbon steels, high-carbon steels and tool steel (silver steel).

Where are they used?

They are used in manufacturing parts and machines for various industries.

5. What gives the addition of manganese, silicon and chromium to steel?

Manganese gives extra strength and tough­ness. Steel containing 4 per cent silicon is used for trans­former cores or electromagnets. The addition of chro­mium gives extra strength and corrosion resistance.

6. What can be made of mild steels (medium-carbon steels, high-carbon steels)?

Low carbon steels are used in the manufacture of sheet iron, wire, and pipes. Medium-carbon steels are used as structural steels. Both mild and medium-carbon steels are suitable for forging and weld­ing. High-carbon steels are used in cutting tools, surgical instruments, razor blades and springs.

7. What kind of steels can be forged and welded?

Mild and medium-carbon steels are suitable for forging and weld­ing.

8. How can we get rust-proof (stainless) steel?

We can get rust-proof steels by adding chro­mium to steel.

9. What is used to form a hard surface on steel?

Heating in the presence of carbon or nitrogen-rich materials is used to form a hard surface on steel.

10. What are high-speed steels alloyed with?

High-speed steels are alloyed with chromium and tungsten plus smaller amounts of vana­dium, molybdenum and other metals.

l. This seemed quite easy the towel. 2. He never dried his hands carefully on 3. My cat liked fish. 4. That sounded funny. 5. The students went to the class every weekday 6. I often saw aeroplanes flying over my house. 7. I could see the aeroplane in the sky. 8. The students were in Mr. Priestley's study 9. We understood the story quite well. 10. The children ate too many ice cream 11. This artist drew very good pictures. 12. Lucille never drank tea in the morning. 13. It wasnot often that Hob went to a wedding. 14. That was what Hob said.